"He did a fine job of landing it on the freeway," Parker said. "He said he landed it in a spot between traffic, so he did well."

Parker said mechanical failure was likely to blame for the emergency landing.

"I think this big hole in the top of the engine probably tells the whole story," he said by cell phone from the Mirror Lake exit off the highway, about 20 miles north of Anchorage, where the landing took place.

"Something blew in there," he said, "looks like it threw rods through the top of the engine."